Marie Granberg's elderly father Mario was given last rites before a 2005 heart transplant, but he survived the surgery, as well as numerous fainting spells and cardiac arrests, always bouncing back and astounding his doctors.

But now the biggest challenge for the 74-year-old former stevedore from Staten Island has been finding a trained home caregiver so his wife can keep working and pay their bills.

He requires 24/7 care not covered by Medicare, and the family has gone through multiple aides, many of them nice, but not skilled.

"My mom had to train them," said Granberg, 45, who works as a paraprofessional. "She is exhausted."

One of the caregivers couldn't even change his diaper properly.

"She put it on backwards," Granberg said. "She actually had turned it over on the glued section and it adhered to his butt."

Another time, her mother came home on her lunch hour and found a young aide outside talking on her phone, while her father languished alone indoors.

"She looked about 18 and couldn't handle him," Granberg said.

Now, a study from Northwestern University finds that agencies that hire caregivers to work with the elderly rarely require or provide training. And, more troubling, many fail to do national criminal background tests or drug testing.

Federal rather than state background checks ensure that criminal offenders -- sexual or otherwise -- can't move between states to find work.

The study, which was published July 13 in the Journal of American Geriatrics Society, found that some agencies even recruit from Craigslist and lie about the qualifications of caregivers who will be paid to work in the home, putting those who are most vulnerable at risk.

"Some are doing an outstanding job and the seniors look perfect," she said. "Others have pressure ulcers and are losing weight, depressed and falling apart. The caregivers are popping gum and playing with their iPhones and could care less."

People have a "false sense of security" when they work with an agency, according to Lindquist. "It's kind of like the wild west -- anybody from a plumber to an architect can set up shop. It's getting worse and it's scary because more people want to stay in their homes longer and it's the best place for most seniors."

Nursing homes are regulated because they accept Medicare dollars, but regulations on home care varies from state to state, according to Lindquist.

"It's a private pay market," Linquist said. Patient families must pay between $25 and $50 an hour for in-home care, and but the agencies take a large chunk, leaving the aide with an average of $7.25 an hour. Private aides, without any middle-man, make $15 to $20 an hour.

Northwestern researchers interviewed 160 agencies, posing as a person who needed a home caregiver and asking about hiring, screening, training and competency assessment.

Only 55 percent of the agencies said they did a federal background check and only one-third said they did drug testing, according to the researchers.

Most agencies relied on self-reporting of experience and only one-third tested applicants for skill competency and waited for "client feedback," the study found.

"How do you expect a senior with dementia to identify what the caregiver is doing wrong?" Lindquist asked.

Jenn, a 38-year-old home caregiver from New Hampshire, who has worked for several agencies and is now with a private home care group, said that in her experience, the study findings are largely true.

"In all my jobs, I have never been drug tested and only once did they do a criminal background check," said Jenn, who did not want to reveal her last name for fear of reprisals from her boss. "I was quite surprised for this line of work that someone would not want to know that."

In her current position, looking after a 93-year-old man with dementia, "I was hired before I even offered up my references and I don't know if they ever checked. She basically wanted to get the position filled. I gave her the information I had, and I was hired on the spot."

Jenn said there had been no formal training. No health care is provided and she makes $15 an hour.

"Since I was hired, I have physically seen [her boss] three times," she said.

"In the past I was CPR trained and have Zen Buddhism and mindfulness coping skills," Jenn said. "I am confident in my abilities, but I am not certified."

Medicine Mix-Ups and Neglect

Study author Lindquist said she has seen examples of neglect in her own medical practice. She said she had a 103-year-old patient whose illiterate caregiver mixed up her own medications and those of the patient.

Another woman dropped 10 percent of her weight and developed bed sores because she was not being properly fed or taken out of bed.

Lindquist's study found that 84 of the agencies she contacted were no longer in business. They had slick websites, but their phones were dead.

"When they make money, they leave the industry after three to five years," she said. "Bosses change or they get out of the field.

"Most people almost try to sell a product and tell us what they thought we wanted to hear," she said.

Some cited phony tests when asked about background checks, including one agency that said it used a "National Scantron Test for Inappropriate Behavior" and an "Assessment of Christian Morality Test" -- neither of which exists, Lindquist said.

When asked about drug testing, some agencies told researchers, "Oh no, unless you pay for it."

As for supervision, only 30 percent of the agencies did a once-a-month home check.

"Amazingly, some agencies considered supervision to be asking the caregiver how things were going over the phone or when the employee stopped in to get their paycheck," Lindquist said.

To find a reputable agency, Linquist advises talking to friends and family and get "word of mouth" to get recommendations for good and bad agencies. Private duty nursing associations can also be helpful, but they represent only a small number of agencies and "cannot vet everyone."

Lindquist said ultimately, laws must change to provide more regulation of the industry, but she hopes her study will educate consumers who can put more market pressure on the bad agencies to get out of the home care business.

"We need to expect better things from an agency and a caregiver," she said.

"A lot of people spend more time picking out a car than an agency," Lindquist said. "Think about it -- this is your loved one, your mom, your dad, your grandma. That should mean something."

As for Granberg, after much trial and error, her family has finally found an excellent caregiver for her father.

"We've been through so much," she said. "But the woman we now pay, if she were ever to leave us, I don't know what we would do. She is phenomenally generous and cares about my dad -- she looks out for him."

As for the others, she said, "You try to train these people, but in reality, some of them are lazy or not trained enough or don't know how to deal with people like my dad who has so many issues."